JSFiddle - React, Tailwind, and code Playground

HTML

<div class='wrap'>
    <div class="left">
        <div class="left-main">
            Left
        </div>
    </div>
    <div class="right right-main">
        Right
        <div class="bottom-right">
            Bottom Right
        </div>
    </div>
    <div style='clear:both;'></div>
</div>

CSS

.left {
    float: left;
}
.right {
    float: right;
}
.left-main {
    width:200px;
    height: 400px;
    background-color: red;
}
.right-main {
    width: 100px;
    height: 30px;
    background-color: green;
}
.wrap{
    position:relative;
}
.bottom-right {
    background-color: blue;
    position:absolute;
    bottom:0;
    left:0;
}